Gary "The Rat" Andrews is a self-centered, misanthropic defense attorney who awakens one morning to find that he has somehow transformed into a giant bipedal rat. Gary struggles to deal with his transformation and hold on to his status as a high-paid, if mercenary, lawyer. Until Gary figures out why he's like this he has decided to try and function the best he can in a "human" world. Outraged at his new appearance, Truman, a tenant in Gary's expensive apartment building, has hired exterminator Johnny Bugz to get rid of Gary for good.